1. Field of the Invention
The present invention relates to an endoscope system having a plurality of types of optical adapters selectively attached to an endoscope insertion unit for the purpose of observation.
2. Description of the Related Art
In recent years, endoscopes having an elongated insertion unit thereof inserted into a body cavity in order to observe an intracavitary organ or the like or perform various kinds of cures or treatments using, if necessary, treatment instruments passed through a treatment instrument channel have been widely utilized. In the field of industries, endoscopes for industrial use have been widely used to observe or inspect the interior of a boiler, a turbine, an engine, a chemical plant, or the like so as to see if the interior is flawed or corroded.
The endoscopes for the foregoing use include an electronic endoscope (hereinafter, simply, endoscope) having an imaging device that photoelectrically converts an optical image into an image signal, such as, a CCD incorporated in the distal section of the insertion unit. In the endoscope, an image processing unit produces a video signal from the image signal representing a view image picked up by the imaging device, and transmits the video signal to a monitor. Consequently, an endoscopic image is displayed on the screen of the monitor in order to enable observation.
In particular, the endoscope for industrial use has a plurality of types of optical adapters made ready to achieve observation according to a position to be inspected. The optical adapters are dedicated to, for example, direct-vision observation or side-vision observation, large-diameter or small-diameter tubes, or stereoscopic observation for which an observational optical system offers two observational fields of view. The optical adapters can be freely detachably attached to the distal section of the endoscope insertion unit, if necessary. For example, a measuring endoscope system disclosed in Japanese Unexamined Patent Application Publication No. 2001-275934 has various optical adapters attached to an insertion unit thereof according to a position of endoscopic inspection or a purpose thereof.